Converting PSI to pounds per min.

Hi to all. I need to figure PSI to Pounds per min on a pressure transmitter. We were give the scale of 0 to 50 pounds per min and would like to know what that is in PSI. Thank you for your help in advance.

Maintenance Man,

please explain your request better.
from what i read, you want to convert psi (pounds per square inch) to pounds per minute.

is this air, water, oil?

regards,
james

Sorry about that, it is water in a chemical process. We calibrate with water in our hand pump and using a Hart 475. And it is psi (pounds per square inch) to pounds per minute. Thank you sir.

These are not the same units of measure. PSI is a measure of pressure, lb/min is a measure of flow rate. This is not a simple psi times x equals flow kind of conversion.

Maintenance Man said:

Sorry about that, it is water in a chemical process. We calibrate with water in our hand pump and using a Hart 475. And it is psi (pounds per square inch) to pounds per minute. Thank you sir.

Click to expand...

There is still some missing information here. Pounds per Square Inch is a measure of Pressure and Pounds per Minute is a measure of Mass Flow.

The conversion calculation has to have an element or elements that converts or translates from Square Inch (Area) to Minutes (Time). It may be possible, but there is information missing.

Looking forward to more information.

You will have to describe the setup more.

One possible scenario is pressure differential across an orifice plate ( see this as an example )

If that were the case we would need all the data concerning the orifice.

bernie_carlton said:

You will have to describe the setup more.

One possible scenario is pressure differential across an orifice plate ( see this as an example )

If that were the case we would need all the data concerning the orifice.

Click to expand...

Good thought, but for an Orifice Plate the Differential is usually give in INWC (in the USA) rather than PSID. A common DP is 100 INWC which equates to around 3.6 PSID.

PSI is a Pressure Measuring Unit
Pound is a Weight Measuring Unit.
If you know the geometry of the tank (square/rectangular vertical cross section only!), presuming the pressure transducer is located at the bottom of the reservoir then:

P(pressure)= F/A

where
A= Area of the tank bottom
and
F= Hydrostatic force of the liquid column applied at the bottom of the container.

If you know the pressure at the bottom of the tank (PSI) and the Area of the bottom of the tank (square inches) then

F = PA = mg

where

m = mass of the liquid
and
g = acceleration of gravity (approx. 10 meter/second squared) = 3860.89 inches/second squared.

Therefore the mass of the liquid column m will result from

m = PA/3860.89

the weight of the liquid W will be then computed using

W = mg -> W =(PA/3860.89)3860.89 = PA

So the Weight of the liquid column in lbs. will equal the product of Pressure (in PSI) times the Area (in square inches) of the tank.

Take pressure readings every minute, do the PSI-to-LBS math and subtract two consequent values; if more accuracy is needed, take the "samples" more often and average the results.

great math to translate psi to water weight then to a water level colon to volume but i think the op is looking for a flow rate that won't be something he can obtain from the a tank level.

It could be mesured from a standard pumping condition while running the pumps and looking at water level change but their is no way to obtain a real time flow from the level sensor itself as normaly the tank level wouldn't change fast enough to update de reading accurately. It could be used to compile dayly basis volume not much more than that.